Bar code symbols are formed from bars or elements that are typically rectangular in shape with a variety of possible widths. The specific arrangement of these elements defines a character according to a set of rules and definitions specified by the code or symbology used. The relative size of the bars and spaces is determined by the type of coding used, as is the actual size of the bars and spaces. The number of characters per inch represented by the bar code symbol is referred to as the density of the symbol. To encode a desired sequence of characters, groups of elements are concatenated together to form the complete bar code symbol, with each character of the message being represented by its own corresponding group of elements. In some symboligies, unique start and stop characters are used to indicate where the bar code begins and ends. A number of different bar code symboliges exist. These symboliges include, for example, UPC/EAN, code 39, code 49, code 128, code-a-bar, and interleave 205.
Bar codes, however, are not limited to the use of only rectangular shapes. Any form of symbol in which different portions of the symbol have different light reflecting characteristics can be used.
Bar codes are typically scanned to transform the graphic symbol elements into electrical signals, which are then decoded into characters. A scanning system uses a light source, typically a laser, which is directed to the symbol or bar code by a lens or other optical components. The scanner functions by repetitively scanning the light beam in a path or series of paths across the symbol. Scanning systems also include a sensor or photo detector which detects light reflected from the symbol. A portion of the reflected light is detected and converted into an electrical signal, and electronic circuitry or software decodes the electrical signal into a digital representation. The symbol is decoded according to the coding technique used.
A bar code offers several advantages or other data representations. For example, a bar code allows data to be entered into a computer more rapidly. Bar code systems are nearly error-free. Bar code formats also are designed with various forms of error checking built into the code. Bar code systems are described in U.S. Pat. Nos. 5,621,203; 5,621,204; 5,621,647; and 5,623,347.
It is often desirable to assign a unique identification code to a particular object or entity while also creating a separate database record corresponding to the item or entity which contains information concerning the item or entity. To facilitate the use of such records, the records may be correlated to the identification code so that the code can be used to access the record easily. Typically, such records are created separately from the step of attaching the identity tag to the object. Such an approach may be acceptable if only a few items are to be tagged, but can become more laborious as the number of items to be tagged increases. Additionally, creating records in a separate step increases the chances of errors occurring when correlating the record to the corresponding identification code. It would be desirable if a unique identification code can be associated with an object or entity while simultaneously creating a separate record of the association.